Abstract: To address the issues of uncontrollable volume expansion rate and worse pressure-bearing capacity of existing water-swelling plugging agent, a high-elasticity and temperature-sensitive delayed water-swelling plugging agent (PHSAP) was developed through free radical aqueous solution polymerization using acrylamide (AM) and hydroxyethyl acrylate (HEA) as monomers, natural starch as grafting material, N,N'-methylenebisacrylamide (MBA) as crosslinking agent, and bentonite introduced as inorganic rigid particles. The research results indicate that temperature and pH are key factors regulating the water-swelling behavior of PHSAP. Under low-temperature acidic conditions (30 ℃, pH 3), the water absorption mass ratio is only 0.47 times within 24 hours, whereas under high-temperature alkaline conditions (85 ℃, pH 10), it can reach 17.19 times within 24 hours. Additionally, the delayed water-swelling characteristics facilitate the smooth entry of the plugging material into the leakage channel and ease pumping operations. Furthermore, PHSAP exhibits sound elastic deformation capacity and high compressive strength, maintaining a pressure of 2.14 MPa at the compressive strain of 82.56%. Thermogravimetric analysis shows that PHSAP has no significant mass loss below 201 ℃, indicating excellent thermal stability of its molecular chains and functional groups. The plugging experiments confirmed that the plugging slurry constructed with PHSAP can achieve effective sealing in formation pores and fractures simulated by quartz sand of different particle sizes, with a pressure-bearing capacity of no less than 5 MPa. These properties of PHSAP suggest that PHSAP has promising application prospects in addressing complex leakage issues in high-temperature formations of deep wells.